Well-boring apparatus



Nov. 25,1924.

P. BRU NT WELL BORING APPARATUS Filed May 22, 1922 2 Sheets-Sheet l P. BRUNT WELL I/BORING APPARATUS Filed May 22 1922 2 Sheets-Sheet. 2

Patented Nov. 25', 1924.

STATES PER-CY BRUNT, OF ADDISGOMBE, ENGLAND.

WELL-BORING APPARATUS.

Application filed May 22,

According to the invention. I providea cylindrical body or block at the lower end of the drill pipe or boring rod designed to lit loosely within the well casing and carrying at the bottom a bit which, whilst allowing of the passage of the said body through the casing, will expand when below the bot tom of the latter so that it can effect the boring required.

The expansion of the cutters of the bit is advantageously effected by inclined or cam surfaces thereon which co-act with similar surfaces 011 the body when the cutters are moved longitudinally thereof.

In a suitable arrangement for carrying out the invention I form the body in two sections secured together, the top section being tapered to a smaller diameter than the bottom section and having a shoulder at the top end and threaded internally to connect it to the drill pipe or boring rod. The said section. is, moreover, formed with a central vertical hole which is divided into branches which run through the lower section so that the fluid for washing out the debris will run through the body to the bit. The lower section of the body has a central hole to receive a mandrel or rod and spring surrounding the latter. This hole near the bottom of the body is reduced in diameterto provide a seat for the spring, the mandrel passing through the reduced portion of the hole and carrying the cutters at its lower end. A packing gland rests on the spring seat which makes the spring compartment oil-tight so that it provides a bath of oil for the spring. The mandrel is supported on the spring and is held in place by a nut screwed on the top of the said mandrel.

The bit comprises a pair of cutting blades hinged on lugs formed at opposite points of the lower end of the mandrel and provided 1922. Serial No. 562,595.

with inclined surfaces on their opposite sides designed to co-act with inclined sur faces on the lower section of the body, so that the lifting action of the spring on the mandrel will cause the two blades to be swung outward and assume a form similar to a fish-tail bit. To enable the said cutters to be moved towards one another to allow the cutter body to pass through the well casing, traotive force is applied to them to compress the spring and so move the inclines on the cutters away from those on the said body.

The cutters are formed so that when they are in the closed position their extreme out ward cutting points are nearer together than the shanks which fit within the casing so as to avoid contact of the said cutting points with the casing.

To enable the invention to be fully under-- stood I will describe it by reference to the accompanying drawings, in which Figure 1 is an elevation of well boring apparatus in accordance with the invention with the bit expanded for use.

Figure 2 is a view of the underside of the apparatus.

Figure'3 is a sectional elevation thereof.

Figure 4 is an elevation at right angles to Figure 1.

Fi ure 5 is a view similar to Figure but showing the bit contracted.

Figure 6 is an elevation of the lower part of the body or block of the apparatus with the bit detached.

Figures 7, 8 and 9 are, respectively, elevations at right angles and a plan of one of the cutting blades of the bit.

Figures 10, 11 and 12 are, respectively.

elevations at right angles and an underside IL;

View of the mandrel.

Figure 13 is a sectional view of the apparatus showing reamer blades substituted for the cutting blades and Figure 14. is a view, at right angles to Figure 13, of one of the reamer blades detached.

a, b are the two sections respectively of the cylindrical body or block screwed to gether as indicated at c. The upper section a, which is tapered as shown, is formed with a central hole (Z internally screw-threaded to receive the drill pipe or hollow boring rod, not shown. a is the central vertical hole in the section a which divides into branches f, f, the said branches also running through the lower section I) so that fluid for washing out the dbris will pass down the drill pipe or hollow boring rod to the bit, hereinafter described, at the lower end of the body a, b, As, when the two parts a, b of the body or block are screwed together, the b *anch holes f in the part a may not register with those in the part b, I form the upper surface of the part b with a groove ()1 to form a con necting passage between the said two sets of branches.

9 is the central hole in the section b of the body, it is the mandrel or rod arranged centrally therein and is the spring surrounding the Si id rod. is the reduced portion of the hole g near the bottom of the body, within which hole 7' the rod h loosely [its and which provides the shoulder to form a seat for the lower end of the spring 7', the upper end of which supports the washer Z held adjustably in place by a nut m screwed on to the upper end of the said rod 7b. 92. is the packing gland interposed between the lower end of the spring i and the shoulder 7c, the said glandv being in the form of a ring having an annular recess containing leather or other packing 0. This packing enables the compartment or hole g to act as an oil bath for the spring p, 21) are the cutters constituting the bit and q, q are the diametrically opposed lugs on the rod h on which the said cutters are supported or hinged, recesses being formed in the shanks p of the cutters to receive the said lugs. 0 0" are the inclined surfaces on the opposite sides of the shanks of the cutters and s, s are the corresponding inclines on the section b of the body or block which co-act with the said surfaces 9", 1" so that the lifting action of the spring i on the rod it will cause the two cutters p to be swung or forced outwards into the fishtail form indicated in Figures 1 and 3 with their cutting points p at such a distance apart as to cut a hole of larger diameter than the body a, 7) and of such dimensions as to enable the cylindritai-l casing or lining of the well, not shown, to be lowered to follow the cutters. The outward movement of the cutters is limited by ribs y)" thereon contacting with corresponding surfaces 5 on the part 7) of the body.

To enable the cutters 79, p to be moved towardone another into the posit-ion indicated in Figure 5, so that they can be low ered through the well casing it is necessary to apply tractive force to them to compress the spring 2". For this purpose the cutters are formed with inclined holes t, 2? with which any suitable tractive appliance or tool can be engaged.

When removing the boring appliance from the well, it will be seen that the cutters y) will be automatically moved towards each other by the inclined outer surfaces of the shanks of the cutters riding against the bottom edge of the well casing.

The extreme cutting points 79 of the cutters are, as indicated in Figure 5, nearer together in the closed or contracted position than the extreme outer surfaces 1) of the shanks p of the cutters, which surfaces 20 will fit within the well casing during the passage of the boring apparatus there through, so that the said cutting points will be maintained out of contact with the said casing and thus avoid being damaged.

a, a Figures 13 and 1a are the cutters forming the reamer, the said cutters having similar shanks to the cutters p so that they can be expanded or contracted similarly to the latter.

Claims.

1. Well boring apparatus comprising a main body designed to fit loosely within the well casing, and provided at its lower end with oppositely disposed faces inclined downwardly and inwardly, a pair of cutters provided with oppositely disposed shoulders for engaging said inclined faces of the body, to force said cutters upwardly into position to bore a hole of greater diameter than the body, said body being provided with a central cavity constituting an oil compartment and pro-vided at its lower end with an aperture, a pull rod connecting with said cutters and extending through.

the said aperture of the main body into the oil recess, a spring surrounding said rod within the oil recess and interposed between one end of the recess and a part connected with said rod for normally holding said shoulders in engagement with the inclined faces of the body, and packing surrounding said rod within the oil recess to prevent the escape of the lubricant.

2. Well boring apparatus comprising a body consisting of upper and lower sections provided with detachably engaging threaded portions and with transversely disposed annular meeting shoulders surrounding said threaded portions, one of said shoulders being provided with an annular groove, the lower section being provided With a contrally disposed oil recess and with vertically disposed water passages located in the walls of the said oil recess and extending from the said annular shoulder of said section to points adjacent to the bottom thereof, a pair' of cutters located in the lower end of said. lower section, said section and said cutters being provided with means for expanding said cutters when the latter are drawn upward with respect to said lower section, a pull rod connected with said cutters and extending into said oil recess, a spring in said oil recess connected with said pull rod, said upper section of the body being pro vided with a central water passage, and

lllt) branch passages extending therefrom to the said ani'iular shoulder thereof, and adapted to communicate with said annular groove.

3. A well boring apparatus, comprising a main body formed of an upper section and a lower section connected by screw threaded portions, the lower section being provided with a central oil recess, and vertical water passages located in said main body between the oil recess and the-exterior surface of the main body and being connected at the upper end of said lower section by an annular groove said main lower section having at its lower end oppositely disposed inclined faces extending downwardly and inwardly, a pair of cutters having inclined shoulders to engage said inclined faces of the main body, a pull rod connected to said cutters and extending lnto the 011 chamber of the lower section of the main body, a spring in said oil chamber interposed between one end thereof and a part connected with said pull rod, to force the inclined shoulders of the cutters normally into engagement with the inclined faces of the lower body section, and hold said cutters in laterally ex- PERCY BRUNT. 

